In an air-conditioning system that uses cooling/heating water as a thermal medium, the cooling/heating water is produced using electricity, gas, or the like, by a thermal source instrument, where the cooling/heating water that has been produced is fed to a load instrument (the air-conditioning equipment) through a circulating pump, so that the load instrument will blow air of a desired temperature.
In such an air-conditioning system, conventionally automated control for adjusting the temperature of the cooling/heating water generated by the thermal source instrument (the feed water temperature), or the flow rate of the cooling/heating water by the circulating pump, or the like, has been carried out automatically. Conventionally, control (termed “optimizing control,” below) for optimizing the efficiency of the thermal source instrument through adjusting automatically the temperature of the cooling/heating water by the thermal source instrument or the flow rate of the cooling/heating water by the circulating pump, or the like, in order to conserve energy or reduce costs in an air-conditioning system has been known as such automated control.
For example, Japanese Unexamined Patent Application Publication No. 2010-236786 (“the JP '786”) describes an air-conditioning system wherein data on the temperature and amount of energy consumption in a thermal source instrument and a circulating pump are collected and stored periodically, to determine the optimal temperature of the cooling/heating water based on a response surface model created based on those data.
Moreover, for example, Japanese Unexamined Patent Application Publication No. 2013-195000 (“the JP '000”) describes a heat recovery plant system for performing automated control by detecting a problem in optimizing control such as the supply air temperature of the air-conditioning equipment not being turned down adequately, and then, in order to conserve energy, automatically turning down the temperature of cooling/heating water that is set too high.
In recent years there has been the need to be able to change, through manual operations, cooling/heating water temperatures that are controlled automatically in air-conditioning systems. For example, there have been requests wherein a building manager, operator, or the like of a building wherein an air-conditioning system is installed may wish to change, through a manual operation, the cooling/heating water temperature when a sudden increase or decrease in the air-conditioning load has been forecasted (for example, when there is a possibility that the room temperature in a retail facility, such as a department store, or the like, will rise due to a temporary sudden increase in the number of customers), or when the building manager or operator has decided to set a safer temperature from the respective of energy conservation.
However, in the air-conditioning system of the JP '786, no thought whatsoever has been given to manually changing the cooling/heating water temperature that has been determined through optimizing control. Moreover, in the heat recovery plant system of the JP '000, even though it is possible to detect a problem in the air-conditioning equipment and to correct automatically the temperature of the cooling/heating water that is controlled through optimizing control, no thought whatsoever has been given to changing the feed water temperature of the thermal source instrument through a manual operation.
When a cooling/heating water temperature is changed through a manual operation there may be problems such as described below.
For example, in optimizing control, sophisticated calculations are carried out using complex quantitative models, so it is not easy to incorporate partial interventions through manual operations by operators, or the like, and there is the risk that doing so could trigger unforeseeable system errors.
Moreover, even if it were possible to change the feed water temperature for the thermal source instrument through a manual operation, in a case wherein there are multiple thermal source instruments it is difficult for the operator, or the like, to determine the amounts by which to change the feed water temperatures of the individual thermal source instruments. For example, in a case wherein one wishes to reduce the cooling/heating water temperature that is supplied to a load, if there is a thermal source temperature that is producing cooling/heating water at the lower specification limit temperature already, then it would be necessary to calculate the amounts by which to change the feed water temperatures of the other thermal source instruments, excluding that particular thermal source instrument. Moreover, even if it is possible to identify the thermal source instruments for which the feed water temperatures are to be changed, it is not easy to determine the amounts by which to change the feed water temperatures of the other instruments in consideration of the thermal source instrument that is operating at the lower temperature limit.
The present invention was created in order to eliminate problem areas such as set forth above, and an aspect thereof is to enable feed water temperatures of thermal source instruments that are determined through automated control to be corrected easily.